That wire not being connected is one of the reasons you can't get the Pony to idle.
The wire from the Pony needs to be connected to a switched 12 volt supply. In other words, the Pony needs 12volts when the ignition is in the ON position.
The wire from the Pony needs to be connected to a switched 12 volt supply. In other words, the Pony needs 12volts when the ignition is in the ON position.